Process for cleaning ceramic articles

• US 6,296,716 B1
• Filed: 12/22/1999
• Issued: 10/02/2001
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: CoorsTek Incorporated (Trelleborg AB)
• Original Assignee: Saint-Gobain Ceramics & Plastics Incorporated (Compagnie de Saint-Gobain SA)
• Inventors: Haerle, Andrew G., Meder, Gerald S.
• Primary Examiner(s): CARRILLO, BIBI SHARIDAN
• Application Number:
  US09/470,510
• Time in Patent Office: 650 Days
• Field of Search: 134/2, 134/3, 134/6, 134/7, 134/28, 134/26, 134/34, 134/36, 134/41, 134/42, 134/902, 451/38, 451/39, 451/75, 451/102
• US Class Current: 134/7
• CPC Class Codes: B24C 1/003 using material which dissolves or changes phase after the treatment, e.g. ice, CO2
• CPC Class Codes: B24C 1/086 Descaling; Removing coating films
• CPC Class Codes: B24C 3/322 for electrical components
• CPC Class Codes: C04B 35/00 Shaped ceramic products characterised by their composition porous ceramic products C04B38/00; ceramic articles characterised by particular shape, see the relevant classes, e.g. linings for casting ladles, tundishes, cups or the like B22D41/02; ceramic substrates for microelectronic semi-conductors H01L23/15; Ceramics compositions containing free metal bonded to carbides, diamond, oxides, borides, nitrides, silicides, e.g. cermets, or other metal compounds, e.g. oxynitrides or sulfides other than as macroscopic reinforcing agents C22C; shaping of ceramics B28B; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products chemical preparation of powders of inorganic compounds C01; infiltration of sintered ceramic preforms with molten metal C04B41/51
• CPC Class Codes: C04B 35/565 based on silicon carbide
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/53 involving the removal of at least part of the materials of the treated article, e.g. etching, drying of hardened concrete C04B41/0036 - C04B41/0054 take precedence
• CPC Class Codes: C04B 41/5346 Dry etching
• CPC Class Codes: C04B 41/5353 Wet etching, e.g. with etchants dissolved in organic solvents
• CPC Class Codes: C04B 41/91 involving the removal of part of the materials of the treated articles, e.g. etching
• CPC Class Codes: C23C 16/4407 Cleaning of reactor or reactor parts by using wet or mechanical methods
• CPC Class Codes: H01L 21/67028 for cleaning followed by drying, rinsing, stripping, blasting or the like
• CPC Class Codes: H01L 21/67069 for drying etching
• CPC Class Codes: Y10S 134/902 Semiconductor wafer

Abstract

A method for cleaning ceramic workpieces such as SiC boats used in semiconductor fabrication is disclosed. The method comprises washing a virgin or used ceramic workpiece with a strong acid and then using a pelleted CO₂ cleaning process on the acid-washed component. The inventive method has been found to produce a workpiece having a very low level of metallic and particulate contaminants on its surface.

Claims

1. A process for cleaning a semiconductor processing component having an inorganic surface, the process comprising the steps of:

a) exposing the inorganic surface to a solvent having at least 1 v/o of an acid selected from the group consisting of HF, acids having a pKa of less than about one, and mixtures thereof, and

b) directing a flow of frozen CO₂ pellets upon the surface, wherein after steps a) and b) are performed the inorganic surface has a metallic contaminant concentration of at most about 600 ppm, as measured by SIMS at a depth of about 10 nm.

2. The process of claim 1, wherein the metallic contaminant concentration other than alkaline and alkaline earth metals is at most about 400 ppn, as measured by SIMS at a depth of about 10 nm.

3. The process of claim 1, wherein the metallic contaminant concentration of iron is at most about 225 ppm, as measured by SIMS at a depth of about 10 nm.

4. The process of claim 1, wherein after the flow of frozen CO₂ pellets is directed onto the surface, the component is installed in a furnace used for processing semiconductor wafers.

5. The process of claim 1, wherein after the flow of frozen CO₂ pellets is directed onto the surface, the component is sealed in a package suitable for storage and transport.

6. The process of claim 1, wherein prior to the step of exposing the inorganic surface to the solvent the component is subjecting to blasting with green SiC particles.

7. The process of claim 1, wherein the inorganic surface is selected from the group consisting of Si, diamond, Y₂O₃, ZrO₂, SiC, Si₃N₄, AlN, Al₂O₃ and quartz.

8. The process of claim 1, wherein the inorganic surface has a vapor-deposited coating thereon.

9. The process of claim 1, wherein the surface is a vapor-deposited material selected from the group consisting of CVD Si, CVD SiO₂, CVD SiC, CVD Si₃N₄, CVD diamond, Y₂O₃ and ZrO₂.

10. The process of claim 1, wherein the inorganic surface comprises a coating provided by sputter deposition or spray coating.

11. The process of claim 4, wherein no additional cleaning steps are carried out between completing the flow of frozen CO₂ pellets and installing the component in the furnace.

12. The process of claim 5, wherein no additional cleaning steps are carried out between completing the flow of frozen CO₂ pellets and packaging the component.

13. A process as in claim 5 which includes the further steps of removing the component from the package and installing the component into a furnace used for processing semiconductor wafers.

14. A process as in claim 13 wherein no additional cleaning steps are carried out between removing the component from the package and installing it into the furnace.

15. A process for cleaning a semiconductor processing component having an inorganic surface, the process comprising the steps of:

a) subjecting the component to blasting with green SiC particles;

b) exposing the inorganic surface to a solvent having at least 1 v/o of an acid selected from the group consisting of HF, acids having a pKa of less than about one, and mixtures thereof; and

c) predicting a flow of frozen CO₂ pellets upon the surface.